1. Field of the Invention
The present invention relates, in general, to lifts for vehicles, and in particular, to low-rise surface lifts for vehicles.
2. Information Disclosure Statement
Establishments or shops where vehicles, such as cars, trucks, and the like, are serviced often need to raise the vehicles from the surface of the shop floor to facilitate the tasks to be performed by a service attendant or mechanic. In many applications, such as vehicle body repair, tire rotation, brake servicing, as well as new and used vehicle preparation and reconditioning, the desired height that a vehicle must be lifted is quite limited, i.e., only to the waist or chest of the repair person. For such applications, use of a "low-rise" surface-mounted lift, as distinguished from a hydraulic lift with a below-ground buried lifting cylinder, is well-known. Such surface-mounted low-rise lifts are typically bolted to the surface of the floor of a service bay in a garage.
A representative well-known example of such a surface-mounted low-rise lift is the model PAL7 surface-mounted low-rise parallelogram lift manufactured and sold for many years by Rotary Lift Company, Memphis, Tenn. The PAL7 lift is designed with parallel front and rear supporting legs pivotally attached to a base and a superstructure, with a hydraulic cylinder that raises and lowers the superstructure and associated vehicle support arms.
However, as such surface-mounted lifts are bolted to the floor of the garage bay, their use is limited to "dedicated bay" applications. A significant capital investment, sufficient to outfit each garage bay with its own dedicated and permanently mounted lift, has been heretofore required by the buyer of surface-mounted lifts.
It is therefore desirable to have a portable surface lift for a vehicle that may be easily moved from garage bay to garage bay, as required, thereby reducing the number of surface lifts required by a given establishment, yet which remains stable beneath a vehicle when in use. Rather than requiring wheels to be attached and removed every time the lift is moved, the lift should be able to be moved into place, preferably moving under a stationary vehicle, yet remain safely in position and not move when lifting that vehicle. It is also desirable to have towing means removable from the lift for moving the lift from one location to another.
A preliminary patentability search in Class 254, subclasses 10C, 8C, 9C, 90, and 124 in the Examiner's Group produced the following patents, some of which may be relevant to the present invention: Chiuzzi, U.S. Pat. No. 3,117,765, issued Jan. 14, 1964; Backus, U.S. Pat. No. 3,689,030, issued Sep. 5, 1972; Cray, U.S. Pat. No. 4,445,665, issued May 1, 1984; and Hansen, U.S. Pat. No. 4,901,980, issued Feb. 20, 1990.
Additionally, Harrison, U.S. Pat. No. 3,317,004, issued May 2, 1967, describes a surface-mounted low-rise parallelogram lift with a releasable safety locking mechanism.
While each of the above patents disclose various vehicle lifts, none disclose or suggest the present invention. More specifically, none of the above patents disclose or suggest, in combination, a portable surface lift for a vehicle, and retractable wheel means, including spring biasing means, attached to the lift for rolling movement of the lift over a surface, such as a garage floor, nor disclose or suggest, in combination with such a portable lift, towing means, removably attachable to an end of the lift, for lifting the end of the lift from resting on the garage floor surface and for causing the lift to be rollingly moved.
Chiuzzi, U.S. Pat. No. 3,117,765, describes a wheeled parallelogram geometry lifting device, but shows no retractable wheel means.
Backus, U.S. Pat. No. 3,689,030, describes a wheeled frame straightening machine having a caster at the end of a spring-loaded beam, but does not show the lifting of cars or other vehicles.
Cray, U.S. Pat. No. 4,445,665, describes a trailer-mounted lift having hydraulically extendable wheels, but teaches, at column 6, the removal of the wheels when the lift is used in a garage. Unlike the present invention, the Cray patent cannot allow its lift to collapse to a low height and be wheeled under and from a stationary vehicle.
Hansen, U.S. Pat. No. 4,901,980, describes a portable lift that folds into a trailer configuration having removable wheels with leaf springs. Unlike the present invention, vehicles cannot be raised and lowered on the Hansen device with the wheels attached.